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Search Results: 1 - 10 of 169611 matches for " K. X. Jing "
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An Improved ZMP-Based CPG Model of Bipedal Robot Walking Searched by SaDE
H. F. Yu,E. H. K. Fung,X. J. Jing
ISRN Robotics , 2014, DOI: 10.1155/2014/241767
Abstract: This paper proposed a method to improve the walking behavior of bipedal robot with adjustable step length. Objectives of this paper are threefold. (1) Genetic Algorithm Optimized Fourier Series Formulation (GAOFSF) is modified to improve its performance. (2) Self-adaptive Differential Evolutionary Algorithm (SaDE) is applied to search feasible walking gait. (3) An efficient method is proposed for adjusting step length based on the modified central pattern generator (CPG) model. The GAOFSF is modified to ensure that trajectories generated are continuous in angular position, velocity, and acceleration. After formulation of the modified CPG model, SaDE is chosen to optimize walking gait (CPG model) due to its superior performance. Through simulation results, dynamic balance of the robot with modified CPG model is better than the original one. In this paper, four adjustable factors ( , , , and ) are added to the joint trajectories. Through adjusting these four factors, joint trajectories are changed and hence the step length achieved by the robot. Finally, the relationship between (1) the desired step length and (2) an appropriate set of , , , and searched by SaDE is learnt by Fuzzy Inference System (FIS). Desired joint angles can be found without the aid of inverse kinematic model. 1. Introduction Recently, many approaches have been adopted for generation of bipedal walking gait. Some researches [1–3] adopted a simplified dynamic model to generate walking gait calculated through inverse kinematic model which is complex and hence the computation load is high. Inspired by neural science, some researchers investigated central pattern generator (CPG). The prime reason for arousing their interest is that CPG models provide several parameters for modulation of locomotion, such as step stride and rhythm, and are suitable to integrate feedback sensors. Hence, a good interaction between the robot and the environment can be achieved [4]. According to Ijspeert [4], CPG becomes more and more popular in robot community. Taga et al. [5] integrated feedbacks with neural oscillators for unpredicted environment. Yang et al. [6], Shafii et al. [7], and Yazdi et al. [8] utilized TFS to formulate ZMP-based CPG model as the basic walking pattern of bipedal robot. Or [9] presented a hybrid CPG-ZMP control system for flexible spine humanoid robot. Aoi and Tsuchiya [10] proposed a locomotion control system based on CPG model for straight and curved walking. Farzenah et al. [11] noted that many researches on CPG model are designed for specific motion only and thus cannot generate
Scaling Laws and Transient Times in 3He Induced Nuclear Fission
Th. Rubehn,K. X. Jing,L. G. Moretto,L. Phair,K. Tso,G. J. Wozniak
Physics , 1996, DOI: 10.1103/PhysRevC.54.3062
Abstract: Fission excitation functions of compound nuclei in a mass region where shell effects are expected to be very strong are shown to scale exactly according to the transition state prediction once these shell effects are accounted for. The fact that no deviations from the transition state method have been observed within the experimentally investigated excitation energy regime allows one to assign an upper limit for the transient time of 10 zs.
The Role of Phase Space in Complex Fragment Emission from Low to Intermediate Energies
L. G. Moretto,R. Ghetti,K. X. Jing,L. Phair,K. Tso,G. J. Wozniak
Physics , 1996,
Abstract: The experimental emission probabilities of complex fragments by low energy compound nuclei and their dependence upon energy and atomic number are compared to the transition state rates. Intermediate-mass-fragment multiplicity distributions for a variety of reactions at intermediate energies are shown to be binomial and thus reducible at all measured transverse energies. From these distributions a single binary event probability can be extracted which has a thermal dependence. A strong thermal signature is also found in the charge distributions. The n-fold charge distributions are reducible to the 1-fold charge distributions through a simple scaling dictated by fold number and charge conservation.
Scaling laws, transient times and shell effects in helium induced nuclear fission
Th. Rubehn,K. X. Jing,L. G. Moretto,L. Phair,K. Tso,G. J. Wozniak
Physics , 1996,
Abstract: Fission excitation functions of He-3 and He-4 induced compound nuclei are shown to scale exactly according to the Bohr-Wheeler transition state prediction once the shell effects are accounted for. The presented method furthermore allows one to model-independently extract values for the shell effects which are in good agreement to those obtained from liquid-drop model calculations. The fact that no deviations from the transition state method have been observed within the experimentally investigated excitation energy regime allows one to assign an upper limit for the transient time of 10 zs.
3He- and 4He-induced nuclear fission - a test of the transition state method
Th. Rubehn,K. X. Jing,L. G. Moretto,L. Phair,K. Tso,G. J. Wozniak
Physics , 1997,
Abstract: Fission in 3He and 4He induced reactions at excitation energies between the fission barrier and 140 MeV has been investigated. Twentythree fission excitation functions of various compound nuclei in different mass regions are shown to scale exactly according to the transition state prediction once the shell effects are accounted for. New precise measurements of excitation functions in a mass region where shell effects are very strong, allow one to test the predictions with an even higher accuracy. The fact that no deviations from the transition state method have been observed within the experimentally investigated excitation energy regime allows one to assign limits for the fission transient time. The precise measurement of fission excitation functions of neighboring isotopes enables us to experimentally estimate the first chance fission probability. Even if only first chance fission is investigated, no evidence for fission transient times larger than 30 zs can be found.
The effects of clouds and aerosols on net ecosystem CO2 exchange over semi-arid Loess Plateau of Northwest China
X. Jing, J. Huang, G. Wang, K. Higuchi, J. Bi, Y. Sun, H. Yu,T. Wang
Atmospheric Chemistry and Physics (ACP) & Discussions (ACPD) , 2010,
Abstract: The impacts of clouds and atmospheric aerosols on the terrestrial carbon cycle at semi-arid Loess Plateau in Northwest China are investigated, by using the observation data obtained at the SACOL (Semi-Arid Climate and Environment Observatory of Lanzhou University) site. Daytime (solar elevation angles of larger than 50°) net ecosystem exchange (NEE) of CO2 obtained during the midgrowing season (July–August) are analyzed with respect to variations in the diffuse radiation, cloud cover and aerosol optical depth (AOD). Results show a significant impact by clouds on the CO2 uptake by the grassland (with smaller LAI values) located in a semi-arid region, quite different from areas covered by forests and crops. The light saturation levels in the canopy are low, with a value of about 434.8 W m 2. Thus, under overcast conditions of optically thick clouds, the CO2 uptake increases with increasing clearness index (the ratio of global solar radiation received at the Earth surface to the extraterrestrial irradiance at a plane parallel to the Earth surface), and a maximum CO2 uptake and light use efficiency of vegetation occur with the clearness index of about 0.37 and lower air temperature. Under other sky conditions, CO2 uptake decreases with cloudiness but light use efficiency is enhanced, due to increased diffuse fraction of PAR. Additionally, under cloudy conditions, changes in the NEE of CO2 also result from the interactions of many environmental factors, especially the air temperature. In contrast to its response to changes in solar radiation, the carbon uptake shows a slightly negative response to increased AOD. The reason for the difference in the response of the semi-arid grassland from that of the forest and crop lands may be due to the difference in the canopy's architectural structure.
Nitric Oxide Scavenger Carboxy-PTIO Impaired Memory of Avoidance Conditioning in Goldfish  [PDF]
X. Xu, K. Zmolek
Open Journal of Social Sciences (JSS) , 2014, DOI: 10.4236/jss.2014.25017
Abstract: The long-term potentiation (LTP), an activity-induced increase in the efficacy of neurotransmission, has long been conceived to be a physiological correlate of learning and memory. Investigations of synaptic transmission suggest that the postsynaptic N-methyl-D-aspartate (NMDA) receptor is the upstream mediator of LTP, while nitric oxide (NO), a retrograde messenger from postsynaptic neurons to presynaptic neuron, is the downstream mediator of LTP. Our previous studies showed that microinjections of NMDA receptor antagonist D-AP5 to the goldfish telencephalon prior to trainings impaired learning of avoidance conditioning in goldfish. However, microinjections of D-AP5 to the goldfish telencephalon immediately following trainings did not impair memory of avoidance conditioning. Carboxy-PTIO is a NO scavenger that prevents NO from reaching the presynaptic neurons. The present study investigated the effects of microinjections of carboxy-PTIO to the goldfish telencephalon immediately following trainings on avoidance conditioning. The results showed that microinjections of carboxy-PTIO to the goldfish telencephalon immediately following trainings impaired memory of avoidance conditioning.
Optomechanically-Induced Transparency in partiy-time-symmetric microresonators
H. Jing,S. K. ?zdemir,Z. Geng,J. Zhang,X. -Y. Lü,B. Peng,L. Yang,F. Nori
Physics , 2014, DOI: 10.1038/srep09663
Abstract: Optomechanically-induced transparency (OMIT) and the associated slowing of light provide the basis for storing photons in nanoscale devices. Here we study OMIT in parity-time (PT)-symmetric microresonators with a tunable gain-to-loss ratio. This system features a reversed, non-amplifying transparency, i.e., an inverted-OMIT. When the gain-to-loss ratio is varied, the system exhibits a transition from a PT-symmetric phase to a broken-PT-symmetric phase. This PT-phase transition results in the reversal of the pump and gain dependence of the transmission rates. Moreover, we show that by tuning the pump power at a fixed gain-to-loss ratio, or the gain-to-loss ratio at a fixed pump power, one can switch from slow to fast light and vice versa. These findings provide new tools for controlling light propagation using nanofabricated phononic devices.
Reduction of heart rate by omega-3 fatty acids and the potential underlying mechanisms
Jing X. Kang
Frontiers in Physiology , 2012, DOI: 10.3389/fphys.2012.00416
Abstract: An elevated resting heart rate is one of the strongest predictors of cardiovascular mortality and is independently associated with sudden cardiac death (SCD). Agents capable of reducing heart rate without significant side effects are therefore of particular interest for the prevention of SCD. Recent human and animal studies have shown that omega-3 fatty acids can reduce heart rate. Our work has shown that omega-3 fatty acids significantly reduce membrane electrical excitability of the cardiac myocyte by lowering its resting membrane potential and the duration of the refractory period through inhibition of ion channels. We propose that these actions may be the underlying mechanisms for the omega-3 fatty acid-induced reduction of heart rate observed in both humans and animals. The heart rate-lowering capability of omega-3 fatty acids may contribute to their preventive effect against SCD.
Dynamics of Cytokines Associated with IL-17 Producing Cells in Serum and Milk in Mastitis of Experimental Challenging with Staphylococcus aureus and Escherichia coli in Dairy Goats
X.Q. Jing,Y.Q. Zhao,C.C. Shang,Y.L. Yao,T.T. Tian,J. Li,D.K. Chen
Journal of Animal and Veterinary Advances , 2012, DOI: 10.3923/javaa.2012.475.479
Abstract: Interleukin-17 is a critical pro-inflammatory cytokine in the development of autoimmunity and the immune responses against infection of bacteria, fungus and parasites. In the present study, dynamics of IL-17 and cytokines associated with IL-17 producing in serum and milk in experimental mastitis challenged with S. aureus and E. coli in dairy goats were monitored using commercial ELISA kits. The results showed that the levels of IL-17 in milk were peaked at 24 or 48 h post challenged with E. coli or S. aureus, respectively but no detectable peak was found in serum. The levels of TGF-β, IL-6 and IL-1β in milk were elevated in goats challenged with E. coli or S. aureus but only slight fluctuant were found in serum. These indicated that IL-17 was an important cytokine in the inflammation development of dairy goat mastitis challenged with E. coli or S. aureus and the local pro-inflammatory cytokines milieu plays an important role in the development of subclinical mastitis whether infected with E. coli or S. aureus.
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